As part of my homework of research on this, research is one of the most fun things to do with scale modeling I think. Sometimes I enjoy it more. I can never have to many pictures. Yes I'm a right clicker. :evil:
I start with internet research. Google is my friend on research, Facebook is becoming a good source for pictures and units. You have guys/gals sharing on pages there. Military unit web pages sometimes have something, every now and then you can get a good a count on how equipment was used. For cars Ebay Motors and auction sites are great. Internet is a good way to locate books on subjects Amazon and Ebay is where I generally go first for books.
On the M25 I kinda knew I wanted the LCM 3 on the back, I just can't pass that up. I started with Google and entered Rhine crossing WWII, then US Navy at the Rhine, then LCM on Dragon Wagon and so on. Most of the time I got the same pictures or information, but one picture of a White 6X6 I clicked on took to a page about the M25 and had some neat pictures, so you never know. For detail pictures and walk around type photos I would enter M25, Dragon Wagon, M26, tank transporter, US Army WWII tank transporter, etc to find pictures.
Below are some of sites I've found and book marked for the M25 40 ton tank transporter;
This is one of the better finds for the Dragon Wagon
http://www.easy39th.com/files/TM_9-767_40-ton_Tank_Transporter_Truck-Trailer_M25_1944.pdf
more good ones
http://www.dse.nl/~vrzaob/wc52/joesstory.html
http://www.rootsweb.ancestry.com/~mtygf/county/m26.htm
even a Facebook page
https://www.facebook.com/pages/M25-Dragon-Wagon-in-WWII/417580594992591
Some of the pictures I have found and right clicked to print later
Some in action pictures
this is a great picture,
did you look at the tires and see one is not a combat tire
This is my favorite picture of a LCM 3 on the M25
Walk around shots found on the web that I right clicked
This another nice couple shots of a restored M26 tractor that someone has been out working it. you can see how the chain oil and mud are on the lever operator shield. They say a Dragon Wagon never got lost as it could follow it's own oil trail back.
I found these pictures on Ebay Motors this last weekend of a couple M15 trailer axles for sale
This black tool box is not included with the kit :hmmm but the brackets on the floor are there
I'll post the books later, I got a lead on some that I don't have at a book store in the Denver area. Just happen to be going to Denver this weekend

hyeah